Contradictory psychologist opinions

It is not just the family court that has trouble with confusing and unscientific arguments from psychologists. In yesterday's Supreme Court decision banning the juvenile death penalty, Scalia dissented:

The American Psychological Association (APA), which claims in this case that scientific evidence shows persons under 18 lack the ability to take moral responsibility for their decisions, has previously taken precisely the opposite position before this very Court. In its brief in Hodgson v. Minnesota, 497 U. S. 417 (1990), the APA found a "rich body of research" showing that juveniles are mature enough to decide whether to obtain an abortion without parental involvement. Brief for APA as Amicus Curiae, O. T. 1989, No. 88-805 etc., p. 18. The APA brief, citing psychology treatises and studies too numerous to list here, asserted: "[B]y middle adolescence (age 14-15) young people develop abilities similar to adults in reasoning about moral dilemmas, understanding social rules and laws, [and] reasoning about interpersonal relationships and interpersonal problems."

The 5-4 majority just picks and chooses whatever psychological expert opinion happens to match their personal poltical prejudices.